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Web开发者需要注意的变化

HTML

The range state of the <input> element (<input type="range">) has been implemented, behind the preference dom.experimental_forms_range, only enabled by default on Nightly and Aurora channel (bug 841948).

The support for the <template> element, part of the Web component specification has been implemented (bug 818976).

JavaScript

Asm.js optimizations are enabled, making it possible to compile C/C++ applications to a subset of JavaScript for better performance.

Firefox Developer Tools

Font inspector shows which fonts on your computer are applied to the page.

Visual paint feedback mode shows when and where a page is repainted.

The dev tools may now be docked to the right side, not just the bottom of the browser.

Some panes within the dev tools have switched from XUL to HTML. For example, the css rule viewer is now chrome://browser/content/devtools/cssruleview.xhtml, not cssruleview.xul. Instead of adding an overlay directly to extend features of these panes, you may add an overlay and script to the outer xul document, to add load listeners and change these html documents.

The stack trace is now shown as a breadcrumb near the top, and the script listing is now at the left panel of the debugger.